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Li metal anode holds great promise to realize high-energy battery systems. However, the uncontrollable Li dendrites formation and infinite volume changes of Li severely hinder its practical applications. Herein, a 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed to guide uniform Li plating/stripping and accommodate a large amount of Li metal. Phase evolution mechanism reveals that lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. Through the conformal incorporation of LiZn alloy, the Li affinity of carbon fibre has been improved significantly, which reduces the Li nucleation barrier and enables homogeneous Li nucleation and growth surround the carbon fibre, forming a conformal CF@LiZn@Li structure at initial stage. The 3D lithiophilic CF@LiZn scaffold with interconnected pores serves as robust host for high Li loading with small volume fluctuation, resulting in a dendrite-free Li metal battery with high areal capacity (up to 12 mAh cm−2). Moreover, the CF@LiZn electrode exhibits a high Coulombic efficiency of 97.1% at 5 mA cm−2, long cycle life of 280 cycles at 2 mA cm−2 and excellent rate performance (∼70 mV voltage hysteresis at 5 mA cm−2). Furthermore, excellent cyclability and rate performance are realized in full-cell batteries with CF@LiZn–Li anode and LiFePO 4 cathode. This work demonstrates a low-cost and lithiophilic alloy matrix for the fabrication of stable Li metal anode toward next-generation high-energy battery systems. A 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed to guide uniform Li plating/stripping. Phase evolution mechanism reveals that lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. The 3D lithiophilic CF@LiZn scaffold serves as robust host for high Li loading with small volume fluctuation, resulting in a dendrite-free Li metal battery with high areal capacity, high Coulombic efficiency, long cycle life. [Display omitted] • A 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed as the host material for Li metal. • Lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. • The 3D lithiophilic CF@LiZn scaffold enables a dendrite-free Li metal battery with high areal capacity and long cycle life. [ABSTRACT FROM AUTHOR]

• S vacancy and heterojunction simultaneously tune the electronic structure of MoS 2. • MoS 2-x affords fast Li+ diffusion kinetics. • Co 9 S 8-y provides strong chemisorption for LiPSs. • The Mo-S-Co heterojunction effectively catalyzes the LiPSs conversion. • S vacancy and heterojunction co-engineering enable excellent performance. The intelligent design of catalytic materials with unique architectures has a significant impact on regulating the polysulfides (LiPSs) conversion and boosting the performance of Li − S batteries. Here, starting from 2D catalytic MoS 2 nanosheets and combined with the first-principle calculations, the covalent heterojunction and S vacancy are simultaneously developed in MoS 2 to regulate the electronic structure and improve the LiPSs conversion kinetics. The S vacancy and heterojunction (MoS 2-x -Co 9 S 8-y) engineering can significantly improve the electrical conductivity of MoS 2 by incorporating shallow donor levels into the MoS 2. Moreover, the incorporation of Co 9 S 8-y greatly improves the chemisorption ability of heterostructure towards LiPSs. The LiPSs are preferentially adsorbed at the catalytic Mo-S-Co heterojunction, where both Li+ and e- are easy to access. The coupled fast Li+/e- transportation of MoS 2-x -Co 9 S 8-y enables direct and fast LiPSs "adsorption-conversion" at the catalytic Mo-S-Co heterojunction with enhanced bidirectional catalytic properties. Due to the ingenious co-engineering of S vacancy and heterointerface, the Li − S cell with MoS 2-x -Co 9 S 8-y /rGO interlayer delivers high sulfur utilization (1382.5 mAh/g at 0.1C), excellent rate capability (710.2 mAh/g at 3C), and long cycle life over 600 cycles (0.06 % capacity decay per cycle). This work demonstrates the great potential of anion deficiency and heterojunction co-construction for high-performance Li − S batteries. [ABSTRACT FROM AUTHOR]

• A co-construction of edge site construction, hybrid phase engineering, and Se anion substitution has been proposed to design the catalyst. • The vertically grown nanosheet configuration ensures that every nanosheet participates in chemical adsorption and catalytic reaction. • The 1T/2H hybrid phase possesses high electronic conductivity and ultra-stable crystal structure. • The Se anion substitution enhances the Li+ diffusion kinetics and significantly reduces the Gibbs free energy for the Li 2 S 4 → Li 2 S 2 rate-limiting step. • Detailed theoretical calculations were carried out to assess the catalytic properties of the catalysts. Applying catalytic materials in Li-S batteries can effectively enhance the lithium polysulfides (LiPSs) conversion kinetics and suppress the severe LiPSs shuttle effect. However, optimizing the catalytic activity of catalysts through synchronous geometrical/electronic structure design remains challenging. Here, we demonstrate that the highly stable MoSSe@graphene (MoSSe@rGO) electrocatalyst, with vertically aligned geometry configuration, 1T/2H hybrid phase engineering, and Se anion substitution, can effectively trap and catalyze the LiPSs conversion. The vertically grown MoSSe nanosheets on rGO expose abundant active edge sites and ensure that every MoSSe nanosheet participates in chemical adsorption and catalytic reaction. The 1T/2H hybrid phase possesses high electronic conductivity, enabling direct and fast adsorption/catalyzing of LiPSs. Moreover, the Se anion substitution in 1T/2H-MoS 2 enhances the Li+ diffusion kinetics and accelerates the LiPSs redox reaction. Due to the synergy of geometrical (edge sites) and electronic (1T/2H phase and Se substitution) engineering, the 1T/2H-MoSSe@rGO affords strong chemical adsorption and enhanced bidirectional catalytic activity toward LiPSs, endowing the Li-S batteries with ultra-small voltage hysteresis (125 mV at 0.2 C), ultrahigh rate capability (747.2 mAh g−1 at 3 C), and long cycle life over 500 cycles. Further, theoretical simulation and ex-situ measurements verify the catalysis mechanism of 1T/2H-MoSSe@rGO and demonstrate its ultra-stable operation upon cycling. This work provides a geometrical/electronic multi-construction strategy to design superior Li-S catalysts. [ABSTRACT FROM AUTHOR]